Convergence defects in patients with temporomandibular disorders.

The aim of this study is to show the presence of a correlation between ocular convergence defects (OCD) and temporomandibular disorders (TMD) among a group of adult subjects. The group studied was made up of 48 subjects (12 males and 36 females). The average age was 35 with a range of 19-45 years of age. The subjects presented with TMD and muscular pain and/or dysfunction. Forty-eight subjects with TMD for the case study were matched by gender and age to 48 control subjects seeking routine dental care (control group). All the subjects were examined by the same orthoptist who classified the ocular convergence degree using two tests. The first test evaluated the distances (in centimeters) of the convergence near point (3-4 cm: normal; 5-7 cm: sufficient; > 7 cm: insufficient). The second test assessed the fusional convergence using a Berens prism test (> 25 diopters: normal; between 18-25: sufficient; < 18 diopters: insufficient). In the TMD group, 36 subjects (75%) showed a compromise of convergence: 13 (36%) were classified in the 5-7 degree range and 23 (48%) in the > 7 cm degree range. The Berens test showed ten subjects (28%) in the group < 18D and 26 (72%) in the group 18-25D. The control-group presented ten (21%) subjects with compromise of convergence: three classified in the group < 18D and seven in the group 18-25D. The TMD subjects presented a higher statistical percentage (p < 0.0001) of ocular convergence defects. The TMD patients also reported a strong association referred to specific signs and symptoms, i.e., limited maximal opening or myofascial pain. There were some subjective reports also of headaches and torcicollis (neck stiffness) which appeared significantly more frequently in subjects with a compromise of convergence. The study showed a much higher prevalence of ocular convergence defects in patients with head, neck, and shoulder pain.